Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
  • B60G17/015—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements
  • B60G17/0152—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements characterised by the action on a particular type of suspension unit
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
  • F16F9/32—Details
  • F16F9/44—Means on or in the damper for manual or non-automatic adjustment; such means combined with temperature correction
  • F16F9/46—Means on or in the damper for manual or non-automatic adjustment; such means combined with temperature correction allowing control from a distance, i.e. location of means for control input being remote from site of valves, e.g. on damper external wall
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
  • B60G2400/10—Acceleration; Deceleration
  • B60G2400/102—Acceleration; Deceleration vertical
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
  • B60G2400/20—Speed
  • B60G2400/206—Body oscillation speed; Body vibration frequency
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
  • B60G2400/50—Pressure
  • B60G2400/51—Pressure in suspension unit
  • B60G2400/518—Pressure in suspension unit in damper
  • B60G2400/5182—Fluid damper
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2500/00—Indexing codes relating to the regulated action or device
  • B60G2500/10—Damping action or damper
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2600/00—Indexing codes relating to particular elements, systems or processes used on suspension systems or suspension control systems
  • B60G2600/18—Automatic control means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2600/00—Indexing codes relating to particular elements, systems or processes used on suspension systems or suspension control systems
  • B60G2600/20—Manual control or setting means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G2600/00—Indexing codes relating to particular elements, systems or processes used on suspension systems or suspension control systems
  • B60G2600/22—Magnetic elements
  • B60G2600/26—Electromagnets; Solenoids

Definitions

• This invention relates to a piston-type fluid suspension system and more particularly to a piston assembly having a bypass valve for selectively adjusting the damping characteristics of the shock absorber both during compression and rebound strokes of the shock absorber piston.
• Various piston-type fluid shock absorbers have included apparatus for adjusting or controllably varying the shock absorbers" damping characteristics or cushioning effects during compression or rebound of the shock absorber.
• various fluid openings have been disposed in, or otherwise associated with, the shock absorber piston or the piston rod, along with means for selectively opening or closing such fluid openings in order to vary the resistance to hydraulic fluid flowing through the piston or piston end piston rod assembly.
• shock absorber in which the amount of damping forces generated by the shock absorber is adjustable.
• exemplary of a shock absorber for selectively changing the damping characteristics of a shock absorber is U.S. Patent Application Serial No. 322,744, filed March 19, 1989, "Method and Apparatus for Controlling Shock Absorbers", the disclosure of which is hereby incorporated by reference.
• the greater the degree to which the flow of damping fluid within the working chamber is restricted by a piston assembly the greater the damping forces which are provided by the shock absorber. Accordingly, a "soft" compression and rebound stroke is produced when the flow of damping fluid is relatively unrestricted- and a “firm” compression and rebound stroke is produced when the flow of damping, fluid is restricted.
• An object of the shock absorber of this application is provision of a method and apparatus for controlling shock absorbers in which the amount of damping fluid flowing between the upper and lower portions of the working chamber can be controlled with a relatively high degree of accuracy and speed.
• Such apparatus when adjusted would provide enhanced road holding and handling by rapidly changing between "firm” and “soft” rebound and compression conditions.
• Another object of this invention is simplification of the piston assembly by reducing both the number and complexity of the components thereof needed to control the damping forces.
• a by-pass valve is driven by a ported plunger, from a first position, to produce a soft compression stroke and a firm rebound stroke, and to a second position, to produce a firm-compression stroke and a soft rebound stroke.
• the improved piston assembly enhances the road handling ability and/or road holding ability of the vehicle by controlling the damping forces of the shock absorber.
• Another object of the invention is to provide a new and improved piston assembly for a shock absorber that employs a "floating" piston within the piston of an existing shock absorber to control the damping flow conditions.
• the floating piston is a relatively uncomplicated design, economical to manufacture, and is adaptable to a wide variety of adjustment applications.
• Another object of the present invention is to provide a method of apparatus for controlling shock absorbers in which the occurrence of a compression or rebound stroke may be determined by measuring the pressure differential between the damping fluid in the upper and lower portions of the working chamber (i.e., the pressure difference across the piston of the shock absorber) .
• Yet another object of the present invention is to provide a shock absorber whose damping characteristics can be easily and conveniently controlled from a remote or external position relative to the shock absorber and which is adaptable to a wide variety of adjustment actuation applications.
• a controllable fluid shock absorber assembly includes a cylinder defining a fluid pressure chamber, a piston rod slidably movable within the chamber, and a piston secured to the piston rod for movement therewith.
• the piston rod extends outwardly from the chamber, is centrally bored, and has fluid openings to pass fluid.
• the piston comprises a cylindrical piston body that divides the pressure chamber into an upper rebound and a lower compression chamber.
• the piston body has a fluid reserve chamber therewithin which receives a "floating" piston, restricted first flow passages which operate to pass fluid between the upper and lower chambers during respective compression and rebound strokes, second flow passages which operate to pass fluid between the upper and lower chambers via
• the floating piston divides the fluid reserve chamber into upper and lower pressure chambers and includes an internal chamber that defines a passageway to pass fluid from the second passages, through the third flow passages, through the internal chamber of the piston and through the bore of the piston rod.
• the floating piston is controlled by operating pressures found inside the chamber which are routed by a solenoid valve that controls the flow of damping fluid between the upper and lower chambers of the working chamber ' during compression and rebound of the piston.
• An external control unit electrically controls a solenoid valve to move the respective openings of a plunger between a first .and second position to control the flow of damping fluid through first and second flow paths, respectively, relative to the first and second chamber portions.
• the floating piston operates to efficiently and rapidly change the ride characteristics of the shock absorber assembly.
• sensor means used in connection externally with the shock absorber change the ride characteristics of a car depending upon the user's desires.
• Figure 1 is an illustration of an automobile using the method and apparatus for controlling piston-type fluid shock absorbers according to an exemplary preferred embodiment of the present invention.
• Figures 2A and 2B are longitudinal cross-sectional views, respectively, of the upper and lower end portions of the shock absorber according to an exemplary preferred embodiment of the present invention.
• Figure 3 is a partial longitudinal cross-sectional view of the piston assembly shown in Figure 2B and shows a floating piston in the piston assembly being positioned so as to provide a firm rebound.
• Figure 4 is similar to Figure 3 and shows the floating piston being positioned so as to provide a firm compression.
• Figure 5 is similar to Figure 3 and shows the floating piston being positioned so as to provide a soft rebound.
• Figure 6 is similar to Figure 3 and shows the floating piston positioned so as to provide a soft compression.
• FIGS 1-6 illustrate an exemplary embodiment of an adjustable shock absorber according to the present invention, as adapted for providing a damping or cushioning effect between sprung and unsprung portions of the undercarriage of an automobile vehicle, or between other interconnected but relatively movable components of other devices.
• shock absorber refers to shock absorbers in the general sense of the phrase and includes MacPherson struts.
• the automobile 12 includes a rear suspension system 14 having a transversely extending rear axle assembly (not shown) adapted to operatively support the vehicle's rear wheels 18.
• the rear axle assembly is operatively connected to the automobile 12 by means of a pair of shock absorbers 10 as well as by the helical coil springs 20.
• the automobile 12 has a front suspension system 22 including a transversely extending front axle assemble (not shown) to operatively support the vehicle's front wheels 24.
• the front axle assembly is operatively connected to the automobile 12 by means of a second pair of shock absorbers 10 and by the helical coil springs 20.
• the shock absorbers 10 serve to damp the relative movement of the unsprung portion (i.e., the front and rear suspension systems 22 and 14) and the sprung portion (i.e., shown as body 26 in Figure 2A) of automobile 12.
• a mode select switch 28 and an electronic control module 30 are provided.
• the mode select switch 28 is located within the passenger compartment of the automobile 12 and is accessible by the occupants of the automobile 12.
• the mode select switch 28 is used for selecting which type of damping characteristics the shock absorbers 10 are to " provide (i.e., firm, soft or automatic).
• the electronic control module 30 receives the output from the mode select switch 28 and is used for generating electronic control signals for controlling damping characteristics of the shock absorbers 10. By controlling the damping characteristics of the shock absorbers 10, the shock absorbers are able to dampen relative movement between the body 26 and the suspension system of the automobile in such a manner as to optimize both ride and comfort and road handling ability simultaneously.
• shock absorbers 10 are of the type shown and described in conjunction with the hereinabove Application Serial No. 322,774, filed March 13, 1989. In the discussion which follows, the shock absorber will be described briefly and only to the extent needed to identify the novel changes.
• shock absorber 10 comprises an elongated, generally cylindrical, reserve tube 32, a cup-shaped cap 34 which closes the upper end of the tube, and a cup-shaped cap 36 which closes the lower end of the tube, thereby forming a closed chamber to store damping fluid.
• Extending axially through upper cap 34 is a piston rod 38 which is secured to a reciprocating piston assembly 40.
• the piston assembly 40 is axially displaceable within an elongated tubular pressure cylinder 42 which is disposed within the reserve tube 32.
• the pressure cylinder 42 defines a working chamber 44 in which upper and lower portions of the working chamber are, respectively, located above and below the piston assembly 40.
• a teflon sleeve 46 is disposed between the piston assembly 40 and the pressure cylinder 42 to facilitate movement of the piston assembly 40 with respect to pressure cylinder 42.
• the shock absorber 10 is connected at its opposite end portions to the rear axle assembly of the automobile 12 and to the body 26 of the automobile 12. The details of such connection do not form part of this invention, as such, and a suitable construction is fully set forth in the hereinabove referenced patent application.
• the shock absorber 10 further comprises an electrical connector assembly 48 which when operated allows for rapid electrical decoupling of the shock absorber 10 from the electronic control module 30 so that the shock absorber 10 may be replaced.
• the electronic control module 30 and its operation relative to control the shock absorbers is described in detail in the hereinabove incorporated Serial No. 322,774.
• the electrical connector assembly 48 may be of the type which is shown in Figures 8-10 of U.S. Patent Application Serial No. 105,404 filed on October 5, 1987, although other suitable electrical connectors may be used.
• an axially extending piston post 50 and a piston post rod nut 52 are provided.
• the piston post 50 is generally circular in cross-section and extends axially through the central bore 54 (e.g., see Figure 3) of the piston assembly 40.
• the piston post 50 is secured to the piston rod 38 by the piston post rod nut 52.
• a base valve assembly 58 is provided as shown in Figure 2B.
• the base valve assembly 58 comprises a generally cup-shaped pressure cylinder end portion 60 which is disposed coaxially with and adjacent to, the lower portion of the pressure cylinder 42.
• the end portion 60 contains a peripherally upwardly disposed recess which is operable to engage the lower portion of the pressure cylinder 42.
• the pressure cylinder 42 is secured to the recess by a suitable means such as a press-fit. It should be understood, however, that other suitable base valves may be used. *
• Piston assembly 40 is used for controlling the flow of damping fluid between the upper and lower portions of the working chamber 44 and comprises a valve body 68 having a first and second plurality of restricted vertical flow passages 70 and 72, a counter-recessed flow passage 74 in the upper end face of valve body 68, and a counter-recessed flow passage 76 in the lower end face of valve body 68.
• Each flow passage 70 comprises a valve controlled upper outlet end portion 78 and a lower counter-recessed inlet end portion 80.
• each flow passage 72 comprises a valve controlled lower outlet end portion 82 and an upper counter-recessed inlet end portion 84.
• an upper spring disk 86 and a lower spring disk 88 are provided.
• the upper spring disk 86 is disposed adjacent to the upper outlet end portion 78 of the flow passages 70, as well as to the upper inlet end portion 84 of the flow passages 72.
• a first helical valve spring 90 and an annularly-shaped spring seat 92 are provided.
• the spring seat 92 has a radially extending portion 94 as well as an axially extending portion 96.
• the radially extending portion 94 is disposed adjacent to the upper end face of the valve body and against the upper surface of the upper spring disk 86 and superposes the flow passage 74.
• the axially extending portion 96 of the spring seat 92 extends axially from the radially extending portion 94 to a position immediately below the piston rod nut 52.
• the axially extending portion 96 further comprises a flow passage 98 which allows damping fluid in the upper portion of the working chamber 44 to flow therethrough and to the flow passage 74.
• the helical valve spring 90 is disposed between the piston post rod nut 52 and the upper surface of the radially extending portion 94 of the spring seat 92. Valve spring 90 is in compression and forces the radially extending portion 94 of the spring seat 92 against the upper surface of the spring disk 86, which in turn forces the lower surface of the spring disk 86 against and in closing relation against the upper • outlet end portion 78 of the vertical flow passages 70.
• the lower spring disk 88 is disposed adjacent to the lower surface of the piston assembly 40 adjacent to the lower outlet end portion 82 of the vertical flow passages 72 as well as the lower inlet end portion 80 of the vertical flow passages 70.
• the lower spring disk 88 is securedly sandwiched between the lower surface of the valve body 68 and a spring seat 100.
• the spring seat 100 comprises a radially extending first portion 102, a step portion 104, and a radially extending second portion 106, the step portion 102 having a flow passage 108 therein which allows damping fluid to flow therethrough.
• a second helical valve spring 110 biases the spring seat 100 against the lower spring disk 88.
• a disk-shaped spacer 112 is disposed coaxially above a piston nut 114 which threadably engages the piston post 50.
• the second valve spring 110 is disposed adjacent to the outer periphery of the upper portion of the piston nut 114 with the valve spring 110 placing an upward biasing force on the spring seat 100 which in turn places an upwardly directed biasing force on the lower spring disk 88. Accordingly, the lower spring disk 88 is able to limit the flow of damping fluid flowing through the flow passages 72 during rebound.
• the valve body 68 comprises a pair of cylindrical body portions 116 and 118 which are joined together to form an interior fluid reserve chamber 120 and an annular inner piston 122, the valve body being disposed coaxially with the axial centerline of the piston post 50, and disposed on the outer radial periphery of the piston post between the upper spring disk 86 and the lower spring disk 88.
• the upper first body portion 116 comprises a plurality of flow passages 124 which extend coaxially with the axial centerline of the piston post
• the lower second body portion 118 comprises a plurality of flow passages 126 and 128 which extend coaxially with the centerline of the piston post, the flow passages 124 and 126 cooperating to form a continuous vertical flow passage from the upper face inwardly and the flow passages 128 cooperating to form a vertical flow passage from the lower face inwardly.
• the upper body portion 116 includes a plurality of pilot ports 130 and 132 which communicate, respectively, the fluid between the flow passage 124 into the fluid reserve chamber 120 and the fluid reserve chamber 120 into respective openings 134 of the piston post.
• the lower body portion 118 includes a plurality of pilot ports 136 and 138, respectively, to pass fluid from the vertical passages 126 into the fluid reserve chamber 120 and therefrom through an respective openings 140 in the piston post.
• the body portions further include openings 142 and 144, respectively, which communicate fluid between passage 124 and 126 and the fluid reserve chamber 120 and therefrom to vertical passage 128.
• the inner piston 122 is in the form of a two-part disk which is positioned in the fluid reserve chamber to move between upper and lower positions and divide the fluid reserve chamber into upper and lower chamber portions.
• Inner piston 122 basically "floats" between its upper and lower positions and includes a central passageway or annulus 146 which is adapted to be brought into and out from register with openings 142 and 144 to pass fluid from vertical passage 124 and 126 through the fluid reserve chamber 120 to the vertical passage 128.
• a plunger member 148 is disposed coaxially within the piston post 50 and is cylindrical in cross-section, the lower end portion of which includes a region 150 which has a reduced external radius and a plurality of openings 152.
• the region 150 is used to allow damping fluid to flow between the piston openings 134 and pilot ports 132, or piston openings 140 and pilot ports 138, and the fluid reserve chamber member 120.
• plunger 148 includes a central pressure passage 154 which allows damping fluid in the lower portion of the working chamber 44 to fluidly communicate through piston post 50.
• an annular coil is provided as discussed in the hereinabove incorporated patent application, the plunger member and the coil forming a solenoid.
• Application of current to the coil causes the plunger to be displaced thereby causing the region 150 to move proximate the respective openings 134 and 140 of piston post 50, the region being appropriately dimensioned to close one opening while the other is open. : is
• the lower chamber 44 is put under high pressure and damping fluid is able to flow through the following flow passages from the lower portion of the working chamber 44 to the region immediately above the upper end face of the valve body: through plunger central passage 154 and through plunger openings 152, through region 150, through pilot ports 138 into the lower half of chamber 120, through pilot ports 136 into passage 126 and 124, and outwardly of flow passage 74.
• the fluid flowing through pilot port 138 into the lower half of chamber 120 is at high pressure, greater than the pressure of the upper half of chamber 120, causing disk to be driven upwardly and cover openings 140 and 142.
• the increased pressure caused by fluid passing through flow passage 70 overcomes the biasing forces of spring 90 thereby causing spring disk 86 to be displaced in an upward direction and uncovering opening 78. This provides a firm compression stroke.
• a pressure sensor is provided to determine whether the shock absorber is in compression or rebound, the sensor being electrically interconnected to signal conditioning units, and to the control module to control the pressure differential between the upper and lower chambers. While details of the control arrangement are provided in Serial No. 322,774, the sensor determines the difference in pressure between the damping fluid in chamber 44 and generates a first electrical signal in response to that difference.
• a second sensor in the form of an accelerometer detects movement of the body of the automobile and generate a second electrical signal in response to that acceleration (or velocity) .
• a control member is provided to receive the electrical signals and generate a command signal directing the plunger to be energized into a first or a second position.
• floating piston 122 could comprise a solid disk of suitable thickness and the openings 142 and 144 of the piston body 68 adjusted appropriately such that the piston, as modified, would divide chamber 122 into two portions and would move from a first position, such as shown in Figures 3 and 4, wherein the disk thickness closes openings 142 and 144, to a second position, such as shown in Figures 5 and 6, wherein the disk thickness uncovers openings 142 and 144.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Vehicle Body Suspensions (AREA)
• Fluid-Damping Devices (AREA)

Applications Claiming Priority (3)

Publications (3)

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ID=24028542

Family Applications (1)

Country Status (5)

Families Citing this family (20)

Citations (3)

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• 1990
  • 1990-04-16 US US07/509,895 patent/US5152379A/en not_active Expired - Lifetime
• 1991
  • 1991-03-05 EP EP91907343A patent/EP0477326B1/de not_active Expired - Lifetime
  • 1991-03-05 JP JP50656391A patent/JP3263070B2/ja not_active Expired - Fee Related
  • 1991-03-05 DE DE69112968T patent/DE69112968T2/de not_active Expired - Fee Related
  • 1991-03-05 WO PCT/US1991/001494 patent/WO1991016556A1/en active IP Right Grant

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Non-Patent Citations (1)

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